Congenital anomalies are not uncommon in the US and around the globe. Whereas some anomalies are well-known, and there’s a lot we know about them, others are relatively poorly explored. This post aims to shed light on congenital anomalies in pediatrics to help you learn as much as possible about this critical subject.
What is a congenital anomaly?
A congenital anomaly is defined as a functional or structural anomaly that develops during intrauterine life, i.e., between conception and birth. Also known as a congenital disability, the genetic anomaly is identified prenatally, at birth, or later in infancy. Anomalies can be mild or severe. However, some are life-threatening, and the affected babies live for a few months only.
How common are congenital anomalies?
According to the CDC, congenital anomalies affect one in 33 babies in the United States. In other words, 3% of babies have congenital disabilities. Since congenital anomalies account for 20% of all infant deaths, they are considered the leading cause of death in newborns.
The World Health Organization (WHO) reports about 6% of babies around the globe are born with congenital anomalies, leading to hundreds of thousands of related deaths. That being said, the prevalence of congenital abnormalities could be even higher because statistics don’t always consider stillbirths and terminated pregnancies.
Due to congenital anomalies, more than 295,000 deaths occur annually in infants under four weeks.
What causes congenital anomalies?
Causes of congenital anomalies can be genetic, environmental, or multifactorial. Genetic causes of congenital disabilities include chromosomal aberrations like those in Down syndrome and Mendelian single-gene defects. In these cases, defects occur due to too many or too few chromosomes, or they result from structural problems in the chromosomes.
Genetic causes also include dominant inheritance, where one parent passes along a single faulty gene, and recessive inheritance, wherein both parents, who don’t have the disease, pass along the gene for the disease to the child.
The risk of genetically caused congenital disabilities is more prevalent in cases of consanguineous marriages and women giving birth after 35 years of age.
Environmental causes of congenital anomalies include maternal diseases, infectious diseases, alcohol and drugs, environmental pollutants.
Multifactorial causes of congenital anomalies refer to gene-environmental interaction, i.e., a genetic predisposition triggered by environmental risk factors. The multifactorial causes account for many congenital disabilities, including cardiovascular malformations, neural tube defects, orofacial clefts, etc.
Types of congenital anomalies
Congenital anomalies are classified into structural and developmental issues. The latter involves conditions caused by an impairment in physical, language, learning, and behavior areas. While many developmental issues such as Down syndrome are congenital anomalies, some are not.
Besides Down syndrome, which affects one in 700 babies in the US-born with an extra chromosome, developmental issues include visual and/or hearing impairments, cerebral palsy, genetic disorders, muscular dystrophy, and specific language impairment.
On the other hand, structural anomalies include spina bifida, heart defects, cleft lip or palate, and clubfoot.
Below, we will discuss the most common congenital anomalies in pediatrics based on the areas they affect.
Brain or spine defects:
- Anencephaly – a serious congenital anomaly wherein a baby is born without parts of the skull and brain. It belongs to a group of neural-tube defects. This congenital anomaly is caused by a closure failure in the cranial neuropore between the third and fourth week of pregnancy.
- Encephalocele – a sac-like projection or protrusion of the brain and membranes that cover the brain through an opening in the skull
- Spina bifida – occurs when the spine and spinal cord don’t develop properly. This congenital anomaly results in severe neurologic dysfunction and leads to functional limitations in adulthood.
When it comes to congenital anomalies that affect the eyes, anophthalmia and microphthalmia are good examples. In anophthalmia, a baby is born without one or two eyes, wherein microphthalmia is a birth defect wherein one or both eyes fail to develop fully.
Heart congenital anomalies are numerous, but the most common examples are:
- Atrioventricular septal defect – the presence of holes between the chambers of the right and left sides of the heart and incorrect formation of the valves that regulate the flow of blood between these chambers
- Coarctation of the aorta – a part of the aorta is narrower than usual. This anomaly needs quick treatment because it can cause hypertension and an enlarged heart.
- Hypoplastic left heart syndrome – affects normal blood flow through the heart. This congenital anomaly is deadly without surgery.
- Single ventricle – baby is born with a heart that only has one ventricle that is big enough to pump the blood effectively.
- Pulmonary atresia – a birth defect where the heart valve that regulates blood flow from the heart to the lungs doesn’t develop at all
Other heart-related congenital anomalies include Ebstein anomaly, tricuspid valve atresia, transposition of the great arteries, among others.
Common mouth defects include cleft palate and cleft lip with and without cleft palate. The cleft lip occurs when the tissue that comprises the lip doesn’t join completely before birth, thus causing an opening in the upper lip. On the other hand, cleft palate happens when the tissue that makes up the palate in the mouth doesn’t join completely during pregnancy. Babies with these anomalies need treatment at the right time and age to achieve esthetic and functional wellbeing.
Stomach and intestine defects include primarily esophageal atresia and tracheoesophageal fistula and rectal and large intestinal atresia or stenosis. The esophagus doesn’t develop properly in esophageal atresia, whereas the tracheoesophageal fistula refers to a defect wherein these tubes are abnormally connected.
Muscle and bone defects include clubfoot wherein a foot turns in instead of being straight, limb defects, diaphragmatic hernia, omphalocele, and gastroschisis. The latter involves intestines found outside the baby’s body exiting through a tiny hole beside the navel. Omphalocele is also where some organs stick outside the body through a tiny hole.
Are congenital anomalies treatable?
The cure for congenital anomalies doesn’t exist. However, early treatment and pediatric surgery can correct many structural anomalies. These treatments help reduce the severity of defects and may improve the quality of life of the affected baby. It is worth mentioning that congenital anomalies are a major cause of disability in children. While many of them can be treated to some extent, others cannot.
Congenital anomalies are common across the globe. Causes of anomalies are often unknown, but a combination of environmental and genetic factors plays a role in many cases. No treatment would wipe out anomalies entirely, but early treatment and pediatric surgery can help control the severity of the defect. Unfortunately, many cases of birth defects are not diagnosed and treated in a timely manner. With congenital anomalies, timing is crucial.